The gigantic skull of a long-extinct species that once roamed the forests of England and Ireland.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.

One of the figures in this Celtic sculpture continues to puzzle archaeologists.

This historic building displays the remains of a victim of the devastating 14th-century plague.

These marks in Myddelton Passage aren't your run-of-the-mill vandalism, and they weren't made by your typical vandal.

An unassuming London park is actually a pilgrimage site for modern clowns.

This 1920s Dutch barge is now a floating bookstore.

Black cat statues guard this temple-like Egyptian revival factory.

Catacombs turned marketplace.

An exercise in radical design and social living that became the epicenter of Soviet spy networks in London.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

This studio was home to David Bowie's first single, even if it did turn away the Beatles.

This secluded walkway overlooks a magnificently wild London green space.

An eccentric 18th century naval officer built a ship's quarterdeck on his roof, the inspiration for Mary Poppins's "Admiral Boom."

This haunting sculpture was created as a statement on the mechanized warfare of the First World War.

This unique bridge curls up like a caterpillar to let boats pass and then unfurls again to span a small canal.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

This ancient oak plays host to carvings of magical elves, gnomes, witches, and other creatures prominent in local folklore.

A relic from one of London's worst 19th-century slums.

A haunting painting meant to capture the calamity of World War I.

On a wall in linear London, a plaque hangs at the high water mark of one of the worst floods in fictional Kcymaerxthaereal times.

On October 17, 1814, a 15-ft. wave of beer ran rampant through the streets of London.

This five-star hotel was originally a swanky parking garage.

A haunting monument dedicated to the Royal Naval Air Service and the Fleet Air Arm.